Electric switch



A1194, 1953 J. A. E. MARCOZ 2,647,969

ELECTRIC SWITCH Filed June l, 1950 i F/g. l H92 VMI/Imm,

24 l 7 5 Ff' .7 23 6 g 24 ,a 282 4 75 /2 20 u Patented Aug. 4, 1953 2,647,969 ELECTRIC SWITCH Jean Alphonse Eugne Marcoz, Rueil-Malmaison, France Application J une 1, 1950, Serial No. 165,403 In France July 6, 1949 6 Claims. (Cl. 20G-116) This invention relates to automatically operating electric switchesl circuit-breakers and similar apparatus. It is an object of the invention to provide an electric switch or the like which is simpler and cheaper to construct, more eiiicient and positive in its operation and more versatile in its applications than prior switches of similar Ype- Known automatic switches or circuit-breakers are comparatively complicated units of equipment, including a large number of component parts such as levers, pivots, sliders, pawls, springs, and so on, detracting from the ruggedness and eiciency of the resulting unit and increasing its cost. The chief reason for this intricacy is the necessity of preventing the possibility of retaining the contact elements in closed condition so long as an overload condition persists. While automatic circuit-breaking switches have been constructed in which part of these intermediate elements are eliminated, such simplified switches have the drawback of including an interlock member which is concealed when in its position of use; thus making access diicult and preventing the aixing of seals to the switch, as is sometimes required.

Furthermore, the operation of all such prior switches lacks positiveness and accuracy, owing to the play between the relatively slidable members and the pivots. Moreover, adjustment is diiicult.

This invention provides a switch which is free of these shortcomings.

According to this invention, I provide a switch which comprises a pair of contacts including a Xed and a movable contact, a first meansy biassing said movable contact away from said fixed Contact, and a second means biassing said movable contact into engagement with said xed contact with a force greater than that developed by said first biassing means, and means responsive to the magnitude of the load current adapted, in the case of an overload, to suspend the co-operation between said second biassing means and said movable contact.

According to a feature of the invention, the second biassing means which may be described as an interlock member, is subject to the action of a push-button or the like operable from without and adapted to recondition the switch or similar unit for operation.

The said responsive means adapted to suspend the operative coaction between the movable contact and the second biassing means is preferably provided in the form of a U-shaped bi-metal strip which may be mounted in series with the movable contact.

Thus, according to the invention, the operative connection between the movable Contact and the interlock member is suspended as soon as an overload condition occurs. The movable contact is then urged by the rst biassing means in a contact-breaking direction. The interlock member is actuated in the opposite direction by the biassing force to which it is subjected and thus serves at the same time as an indicating means adapted to warn the operator that the unit is in released or disengaged condition.

The above-described arrangement may be embodied in a single or a multi-pole switch. Each pole may include one or any greater number of circuit breaks in series. It may be made to disengage under thermal, electromagnetic, or any other desired inuence.

The device may be connected with the related conductors through terminals, as in the circuitbreakers in conventional meter-panels. The connection may also be eiected by the use of plugs or jacks, as in the case of safety-plugs or fuses, for which a switch according to the invention may be substituted.

A switch or circuit-breaker according to the invention can easily be accommodated within the base oi a wall-plug for example, or in a iiexible plug-connection, cr it may be made to perform the function of an intermediate safety element interposed between a male and a female member of a plug-connection. It can further be incorporated in a fixed switch or in a movable switch of the type interposed along a exible conductor.

A further advantageous application of the improved circuit-breaker or switch unit may consist of providing it with auxiliary contacts adapted to be automatically opened or closed on operation of the unit, which may accordingly be utilised as a relay.

It will be obvious that the switch unit may have associated with it an operating button whereby the circuit may be broken when desired.

The above and further objects, features and advantages of the invention will be fully understood from the ensuing description of a few exemplary embodiments of the invention, selected by way of indication rather than limitation, and with reference to the accompanying drawings, in which:

Fig. 1 shows one. embodiment of my improved switch device in engaged or cocked condition;

Fig. 2 shows the same device after it has been released;

Fig. 3 relates to a modification;

Figs. 4 and 5 are detail views;

Fig. 6 relates to another modification; and

Figs. l and 8 relate to a construction including an interchangeable bi-metal strip.

As shown in Figs. l and 2, my improved switch device comprises a casing containing a xed contact I and a movable contact 2 supported on a spring-plate 3. An actuating push-button 4 is supported on a spring-plate 5. The springplates 3 and 5 are so mounted under pre-tension that they tend, when left to themselves, to assume the separated condition shown in Fig. 2, with the upper spring applied against the top and the lower spring against the bottom of the casing. They are, however, prevented from doing so in the cocked or engaged condition of the unit by the provision of a latching nose or shelf 5 projecting from a small spring plate shown as upstanding from plate 3. The inherent resilient force of the upper spring plate 5 is greater than that of the lower spring plate 3. Owing to this, vin the cocked condition of the device shown in Fig. 1, the lower element 3 is maintained by the upper element 5 with its movable contact 2 applied against the fixed contact I. In this condition, current flows from an input terminal through the fixed contact I, the movable contact the spring-plate 3 and to outlet terminal 9.

Assuming that an overload arises, the. spring 'I is arranged to .be moved aside by a means responsive to overload, not illustrated, which may consist of a bi-metal strip or any other suitablev known means. The nose 6 then releases the lower spring plate 5, and the contact is broken. Instead of providing a separate overload responsive means, the spring 'I may itself be provided in the form of a bi-metal strip or the like adapted to be heated either directly by current flowing through it or indirectly.

The push-button 4 springs out to a projecting position (Fig. 2.) thus indicating that the device has operated. The spring-plate 3 snaps away to the opposite direction and opens the contact at I2.

To re-cock the device, it is only necessary, after the overload has been relieved, to depress the button 4 fully home and then allow it to move back a little. In so doing, the end of the springplate 5 engages under the shelf 6 and restores the movable contact 2 into engagement with the fixed contact I. If the overload persists, the device operates again without there being any possibility of preventing such action by maintaining pressure on the button 4.

In the form of embodiment illustrated in Figs. 3, 4 and 5, the bi-metal strip IG which, as a result of its deformation, causes the device to operate and disengage the contacts, is supported on the spring-plate 3. Said bi-metal strip is U- shaped, having unequal arms and has secured to the top of its longer arm the movable contact 2. The dimensions on the bi-metal strip and the position of the contact 2 are such that. in the case of an overload, the resulting deformation tends to disengage the nose 6 from the cooperating shelr or hook l, as the result of a pivotal movement about the contact 2 as a centre. The arms of the bi-metal strip close in towards each other and pull the nose 6 in the direction indicated by the arrow f1 (Fig. 5). The shelf 'I is then urged back in the direction f2 and the contact 2 is urged in the direction i3 (Fig. 5) thereby breaking the circuit. The shelf 1, in

the lower spring its upward movement, pushes back the actuating button 4 which was retained in its depressed state per suitable spring means such as the coil spring II.

A circuit-breaking button I2 is further provided. By pressing on this button, with the device in its engaged condition, the lower end I3 of the push-button I2 acts upon an inclined element I4 rigid with the plate 5 and releases the shelf I, thus disengaging the device.

A set-screw l5 is provided to enable adjustment of the relative position between the shelf 'I and the cooperating nose S. Accordingly, it is very simple to adjust the device, as with a screwdriver inserted into the adjusting hole ID. To

vmake such an adjustment, all that has to be done is to place the device under the load correspending to that for which it is desired that it should operate, then turn the screw I5 until it does operate. The device is then set for .the selected load current.

As stated, the unit may further be provided withl auxiliary contacts such as signalling or relay contacts. For this purpose, an insulated nose I? is provided in the position shown, and the nose IT is adapted, when the switch operates, to press down against an auxiliary spring-plate I8 arranged beneath it, provided with an auxiliary movable contact which may thus serve to make or break one or more auxiliary contacts. It will be understood that such auxiliary contacts may be so arranged as to be made or bronen as desired, on engagement or disengagement of the main contacts I-2.

In the further modication shown in Fig. 6, the device is in the form of a safety plug or .fuse provided with connecting plugs 3 and S. The push-button 4 is provided with a shelf or hook I and is slidable over a shank I9 extending up from the plug member 8; the button is urged to its projected condition by a coil spring 2i) or the like. The xed contact I has a top .projection under which the Vmovable contact 2 engages. The movable contact 2 is carried at the end of a spring-arm 5 and is normally urged downwards by the inherent resiliency of said arm. However, a nose 6 rigid with it, is adapted to .be raised by the shelf 'I projecting from the button 4 under the force o the spring 25, more powerful than that of the spring-arm 5, thereby maintaining the movable contact 2 applied against the xed contact I'. It may be seen that in this embodiment, the function of the second biassing means, which in each of the first-described constructions was performed by a spring-arm 3, is here fulillled by the coil-spring 2L. rlhe U- shapedV bi-metal strip IB interposed on the spring arm III operates in a similar manner as in the construction of Figs. 3 to 5. Flow of current is from the plug terminal 8 through iixed contact I, movable contact 2, bi-metal strip I0, spring-plate 5 to terminal plug E.

Figs. 7 and 8 illustrate yet another form of construction, having a particular high breaking capacity and adapted to be equipped with an interchangeable Vthermal responsive element. As shown, the unit comprises two identical pairs of contacts (Ia, 2c and Ib, 2b) in series. The movable contacts 2a and 2b are interconnected by an insulating strip 2I which carries the shelf or hook 1, pivoted about an insulated pin 22 and retained in its vertical position by a small spring 30.

The fixed contacts la and Ib are carried on the insulated plate y23'. They are connected to the respective ends of a bi-rnetal strip 24 which is adapted to deform when subjected to an overload and in its thus deformed condition to press down on the end of the nose 25 rigid with the hook 1, and thus releases this hook which was maintained in its raised condition by the spring plate 5. The contacts 2a and 2b are then urged back downwards down away from ic and lb while the button 4 springs upwards to its projected position.

The insulating part 23 is mounted for slight rotation about a pivot 26 secured to an insulating base-plate 2l. A spring 28 tends to urge the part 23 away from the base 21 about its pivot 26. A set-screw 23', provided with a head 29 constituting a calibrated dial, when rotated causes the part 23 to swing about the pivot 26 and thus to move the bi-metal strip 24 towards and away from the nose 25, thereby to adjust the operating point of the device.

A circuit-breaking button l2 is provided to break the contacts by pressing down on the end of the bi-metal strip 24,

In this embodiment, the pivot 2S may be replaced by a simple knife-edge fulcrum. The part 23 and the bi-metal strip can then be removed simply by unscrewing the set-screw 28. This arrangement makes it possible to provide a set of different gauges of bi-metal strips interchangeably adaptable to a given device according to the invention.

It will be obvious that, if preferred, the bimetal strip may be mounted in an auxiliary circuit to be controlled, which thus will be capable of controlling the operation of the device.

Many other modiiications and variations may be made in the details of embodiment described and the invention may be put to many uses other than those speciiically mentioned, without departing from the spirit and scope of the present application.

What I claim is:

l. In an automatic switch of the type comprising a casing containing a movable and a fixed contact in combination at least one xed con tact, a irst resiliently deformable arm, at least one contact on said arm constituting the movable contact of the switch, said arm being adapted to move said movable contact away from said contact, a second and more powerful resiliently deformable arm adapted to act on said, movable Contact in an opposite direction from said rst arm, co-operating means on both said arms inm terengageable to subject said first arm to the action of said more powerful second arm to engage said movable contact against said fixed contact, and a bi-metal strip inserted in series in the electric circuit controlled by said .switch and adapted by its distortion in case of a current overload to act on said co-operating means for separating them and for releasing thereby said first arm from the action of said second arm, and a pushbutton which is independent of said bi-metal strip, connected to said second arm realising the engagement of said cooperating means and adapted to protrude outside of the said casing as soon as the said cooperating means have been released under the effect of a current overload.

2. In an automatic switch of the type comprising a casing containing a movable and a iixed contact in combination at least one xed contact, a rst resiliently deformable arm, at least one contact on said arm constituting the movable contact of the switch, said arm being adapted to move said movable contact away from said fixed contact, a second and more powerful resiliently deformable arm adapted to act on said movable contact in an opposite direction from said iirst arm, cooperating means on both said arms interengageable to subject said first arm to the` action of said more powerful second arm to engage said movable contact against said iixed contact, and a bi-metal strip inserted in series in the electric circuit controlled by said switch and adapted by its distortion in case of a current overload to act on said cooperating means for separating them and for releasing thereby said first arm from the action of said second arm, and a push-button which is independent of said bi-metal strip, connected to said second arm, realising the engagement of said cooperating means, and adapted to protrude outside of the said casing as soon as the said cooperating means have been released under the eiiect of a current overload and further set screw means acting on the relative positions of said bi-metal strip and said cooperating means to pre-set the operating point of the switch, that is the moment when the switch will open under the effect of an overload.

3. In an automatic switch according to claim l, a base, an insulated support mounted for restricted pivotal movement on said base, the said iixed contact and the bi-metallic strip being secured to said support, spring means biassing said movable support in one direction about its pivot and set-screw means adapted to force said support in the opposite direction thus to pre-set the operating point of said switch.

4. In a switch as in claim 3, wherein said cooperating means comprise a spring-urged arm pivoted on said first arm, a top shelf on said spring-urged arm releasably engaging said second arm, a part projecting from said springurged arm, said bi-metallic strip being adapted when deformed to press upon said projecting part to release said shelf from said second arm.

5. In a switch as in claim i wherein there are two sets of contacts in series, both fixed contacts being supported on said insulating support and an insulating strip interconnecting the arms of both movable contacts and having said springurged arm pivoted thereto.

6. In an automatic switch according to claim l., a further push-button acting on said co-operating means to disengage the same at will when in engaged condition.

JEAN ALPHONSE EUGNE MARCOZ.

References Cited in the iile of this patent UNITED STATES PATENTS Number Name Date 2,483,645 Kitman I Oct. 4, 1949 2,463,646 Kitman Oct. 4, 1949 FOREIGN PATENTS Number Country Date 486,062 Great Britain May 30, 1938 '794,535 France Dec. 12, 1935 

